Last Modified: March 1, 2024

Types of Gravel

Foundations in Landscaping series: part 2

Types of gravel

By Ben Parrot - Landscape Gardener & Amateur Geologist

Overview

Welcome to part 2 of our series, Foundations in Landscaping, which covers design fundamentals for homeowners and the DIY-inclined. Gravel, an often misused and misunderstood term, is a large category of aggregates that plays a central role in our lives, everyday, whether in decorative landscaping and hardscaping, or home-building and construction. Yet, in spite of the omnipresence and importance of gravel in our daily lives, there is very little comprehensive information or agreement regarding the classifications and terminology online today.

As the only encyclopaedia for decorative aggregates, our core mission is to document and classify every type. One of our core aims is also to educate and empower people in search of helpful information about renovating their outdoor space. In this article, we assemble the first comprehensive list of all the major gravel types, from the most practical types of gravel for driveways through to the demystification of the many types of landscaping gravel retailing in the UK today.

Gravel blend with sea shells. Jpg

Key Takeaways

  • Get the list of every type of gravel available to gardeners in the UK.
  • Find out the different sizes for grading gravels.
  • Get an overview of each different type with links to examples.
  • Find out about our innovative tool for finding every option of gravel available by colour or material, called Pebble Picker.

The Complete List: 23 Different Gravel Types

Below is 'our list'. While there is bound to be some controversy in geological quarters over potential inconsistencies, or duplication within, we have followed a methodology based on the ideas of inclusivity and contemporary, online hierarchies. Specifically, we have included terms that refer to multiple types of gravels, just like in real life. One only needs to visit a few online suppliers to see the disagreement. Therefore, it is necessary to represent how they are used online in search queries or as particular 'entities' as classified by search engines.

  1. 1
    Crushed gravel
  2. 2
    River rock
  3. 3
    Pea gravel
  4. 4
    Stone chippings
  5. 5
    Resin-bound gravel
  6. 6
    Slate chippings
  7. 7
    Washed gravel
  8. 8
    Pea shingle
  1. 9
    Crushed rock
  2. 10
    10mm gravel
  3. 11
    20mm gravel
  4. 12
    Self-binding gravel
  5. 13
    Ballast
  6. 14
    Decomposed granite
  7. 15
    Stone dust
  8. 16
    Quarry process
  1. 17
    Driveway gravel
  2. 18
    Marble chips
  3. 19
    Cotswold gravel
  4. 20
    Basalt gravel
  5. 21
    White gravel
  6. 22
    Drainage gravel
  7. 23
    Lava gravel

So there is the complete list in all its glory. Before we go into detail about each type, we briefly cover the use of gravel by sector to offer some context that may help some newbies.

Gravel and chippings

Common Uses of Gravel

In this section, we delineate between the different types of gravel for gardens, and those more used for building and construction purposes, before offering a standardised guide to gravel sizes, which we also cover in more detail, application by application, in the first part of our series, 'Foundations in Landscaping', called Gravel Sizes.

The Types of Gravel for Gardens

Gravel serves multiple purposes in landscaping, from the creation of surfaces for driveways and pathways, to their use as a decorative ground covers and sub-base materials in the construction hardscaping projects. In gardens, it can provide drainage, reduce weeds and add textural contrast. It is also a popular choice as a decorative element around flower beds or as a low-maintenance, feature gravel garden. When it comes to creating borders, the larger sizes of gravel add contrast to plants whilst offering ample coverage over bigger areas. Gravel is also a mainstay of hardscaping and building construction.

Construction Gravel Types

When it comes to construction aggregates, gravel's role is fundamental. The most common types include crushed rock, such as MOT type 1 sub-base, which is one of the most popular types of gravel for a driveway or road base due to its compacting qualities; river gravel, used for its smooth, round shape and cost-effectiveness in concreting and drainage applications; and self-binding gravel, favoured for its natural availability and low-cost durability. Each type of gravel has unique properties suited to specific uses in construction.

Contruction gravel

A Brief Look at Gravel Sizing

Different classifications apply to stone chippings and gravel, depending on their particle size and classification methodology, which can either be ISO or the Udden-Wentworth scale. However, for determining the best sizes for each type of landscaping application, the ISO classifications are more practical and sufficient, and therefore we use them.

International Organisation for Standardisation ISO 14688:

  • Fine gravel: Pea gravel with a particle size greater than 2mm but less than or equal to 6.3mm. (>2mm ≤ 6.3mm).
  • Medium gravel: Gravel particles larger than 6.3mm but smaller or equal to 20mm. (>6.3mm ≤ 20mm).
  • Coarse gravel: Large gravel that consists of particles with a size between 20mm and 63mm. (>20mm ≤ 63mm).

Choosing the Right Type for Your Project

Selecting the ideal gravel type depends on your project's purpose, aesthetic preferences and budget. For driveways, consider a more robust option, like crushed gravel, which packs down well and can withstand heavy traffic. For a garden path or patio, pea gravel or slate chips, with their smoother edges, can provide a more comfortable walking surface. The key is to find the balance between functionality and your desirable aesthetic outcomes.

Panda chips with rockery. Jpg

The Different Types of Gravels

The following list of materials classified as 'gravel' covers the different types of landscape gravel, decorative and construction aggregates and the common types of garden gravel available in the UK. It has been compiled based on contemporary factors such as each item's popularity, proliferation and importance from a professional perspective, as well as the traditional factors to do with the shape or origin of the stone.

It's also worth noting that each of the different types of gravels listed below can also vary by size, colour, shape or base material. You can find out more about them in the hyperlinks throughout. Additionally, with our encyclopaedia you can finally get access to the entire range of gravel types retailed in the UK, offering you so much more scope for customisation than you could imagine. Now, let's dig in!

1. Crushed Gravel

Crushed gravel

We chose to begin with crushed gravel because it is a fundamental type of aggregate produced from the mechanical crushing of base rocks into smaller pieces. A great deal of the following types will be the product of a crushing process. It's characterised by sharp, angular shapes and a rough texture. This type of gravel's angularity helps it to interlock, providing superior stability and very compact surfaces. This makes crushed gravel one of the ideal driveway gravel types, as well as for use as a foundation aggregate for various construction projects. Its unbeatable stability comes at the price of comfort, particularly when barefoot.

Examples include anything from 20mm gravel construction aggregate (see below) through to Ice chippings, a decorative blend.

2. River Rock 

River rock. Jpg

River rocks stones that have been smoothed and rounded by the movement of water in rivers, beaches and streams. When purchasing river rock, the base materials may be sedimentary, igneous or metamorphic rocks. It will generally depend on the supplier and the geography of the waterway they come from. River rocks are often used for decorative purposes in landscaping, such as in gardens, pathways and water features, due to their varied shapes and attractive appearance. Smaller, pea gravel is also popular for pathways.

Examples include crushed granite and Trent gravel, from the Trent river.

3. Pea Gravel

Pea gravel

By definition, pea gravel is a type of gravel that consists of small, smooth and naturally rounded stones, usually 6mm to 10mm (3/8 inch) in diameter. These stones come in various colours and are commonly used for decorative landscaping purposes. Pea gravel is one of the most popular types of gravel for walkways, patios and as a ground cover in gardens due to its pleasing appearance and comfort when walking.

Golden gravel and Staffordshire pink gravel.

4. Stone Chippings

Multi mix spar stone chippings. Jpg

Stone chippings refer to small stones processed by a crusher, that are derived from various rocks and come in many different colours and sizes. They are commonly used in landscaping for creating practical and attractive decorative features, such as pathways and decorative layers in garden beds. Stone chippings are valued for their visual appeal and low-maintenance practical benefits.

Examples include flamingo chippings or blue granite chippings.

5. Resin Bound Gravel

Resin bound gravel

Resin-bound gravel is the combination of fine pea gravel stones and epoxy resin used to create smooth, hardwearing surfaces for walkways, driveways and patios. This type of gravel is known for its durability and permeable quality, allowing water to drain through, reducing puddles and improving water management. Resin bound gravel kits allow for DIY improvements to old concrete surfaces and can offer a sleek, modern finish that is very customisable due to a variety of colours.

Examples include 3mm white spar gravel.

6. Slate Chippings

Slate chippings

Slate chippings come from slate, which is a fine-grained, durable stone that splits easily into thin layers. It is often used in decorative landscaping due to it's beauty and durability, especially in patios, pathways and garden beds. Slate comes in various colours, such as blue, grey, green and purple. It is known for being fish-friendly, fire-resistant and very cost-effective.

Plum slate chippings and grey slate chippings.

7. Washed Gravel

Washed gravel

Often also called 10mm/20mm shingle, washed gravel is a budget aggregate that has been washed to remove dust and fines. This process improves its appearance and quality, making it suitable for both decorative purposes and drainage systems. Washed gravel is often used as a cost-effective landscaping material for pathways and driveways, as well as a top dressing for garden beds.

Examples include 20mm Washed Gravel and river gravel.

8. Pea Shingle

Pea shingle. Jpg

Pea shingle, also mistakenly referred to as pea gravel, are small, round to sub-angular type stones with one end wider than the other, a bit like a rounded triangle shape. Shingle gravel can range in size from 6-30mm and be composed of many types of naturally formed stones. Due to it's shape, it doesn't interlock and pack down like other shaped gravels, making it most popular for use in decorative landscaping due to its attractive appearance and versatility. It's also great for drainage systems and construction jobs like concreting.

Pea shingle and 20mm shingle gravel.

Need to work out how much gravel your project needs? Try our free gravel calculator.

9. Crushed Rock

Crushed rock

Crushed rock is a rough type of construction aggregate that goes under many names, including hardcore and crusher run. It is produced by mining rock deposits and breaking them down to the desired sizes using a crusher. It is widely used in various construction activities, including as a base for roads, in concrete and as an aggregate in asphalt. MOT Type 1, Type 2 and Type 3 sub-base are commonly available aggregates used in landscaping for the construction of foundations and drainage solutions. They vary by the size of the largest rocks down to dust. Limestone Type 1 is a type of MOT Type 1 made from crushed limestone with similar properties.

Examples include MOT Type 1 sub-base and Limestone Type 1.

10. 10mm Gravel

110mm pea shingle. Jpg

10mm gravel, with its small-sized stones obtained from river rocks or produced from crushing, is one of the most common types of landscape gravel. It is an all-rounder, excelling at most tasks whilst coming in as one of the cheapest options available. It's often used in front garden borders and is a popular choice for garden pathways, providing a relatively stable surface that is softer underfoot than larger gravels. The small, round sized stones also see it widely-used in construction, from concreting to drainage and pipe-bedding.

It is retailed as 10mm gravel or 10mm shingle, and the composition can vary wildly, so always get a sample if aesthetics are a key issue.

11. 20mm Gravel

120mm pea shingle. Jpg

Much like 10mm gravel, 20mm gravel is just larger and more robust, with a higher load-bearing capacity making it widely used in construction and also one of the most well-suited types of gravel for drives and pathways, as its size makes it more stable and less prone to displacement. It is also frequently used for drainage purposes in gardens and as a decorative feature around plants, as a ground cover.

Retailed as 20mm gravel or 20mm shingle, and the composition can vary wildly, so get a sample if aesthetics are an issue.

12. Self-binding Gravel

1self binding gravel

Self-binding gravel contains stones, fines and particles that bind together when compacted, creating a firm but permeable surface. This type of gravel is ideal for creating rustic, natural-looking pathways and outdoor spaces. One type, Breedon gravel is particularly popular in heritage sites and rural settings due to its traditional aesthetic. Self-binding gravel requires less maintenance than loose gravel and can  provide a more level and surface, although it is nowhere near as durable and is prone to getting muddy in wet weather.

Examples include Hoggin self-binding gravel and Cedec gravel.

13. Ballast

Ballast is a mixture of sand and gravel used to create concrete. Typically, the gravel component of ballast is in the 20mm size range. This combination is essential in construction for creating a strong, stable base for buildings, pavements, and roads. Ballast is not commonly used for decorative purposes in landscaping but is an integral part of construction and structural projects.

14. Decomposed Granite - Grano Dust

Decomposed granite is a type of granite rock that has undergone weathering, which causes it to break into smaller pieces, turning it into a mixture of gravel-sized particles, sand and silt-sized particles. It has a natural, rustic appearance and great permeability. However, although available in the USA, the closest products to it for the UK are called grano dust or a granite self-binding gravel.

1grano dust

15. Stone Dust

Stone dust, also known as rock dust, is a finely crushed stone product used extensively in construction and landscaping. It is primarily used as a base material for pavers, driveways and concrete slabs. Stone dust helps to provide a stable and level surface and also reduces voids in the sub-base material. In the UK, it can be used in landscaping projects as a pathway surface that resembles a self-binding gravel.

16. Quarry Process

Quarry process, also known as "QP" or "Dense Grade Aggregate," is a blend of small crushed stones, three-quarters of an inch or less and stone dust. This combination is ideal for use as a sub-base in road construction, driveways and walkways. Due to its low-void content, the crushed stone and dust mixture compacts well and provides a durable and reliable base material.

Examples include limestone quarry process and granite quarry process available directly from quarries.

17. Driveway Gravel

1driveway limestone gravel

While not a conventional 'type', it is highly sought after type of gravel that is typically made up of 20mm angular chippings that compact together, reducing the risk of vehicles causing rutting. The angular shape of the gravel provides better stability underfoot and for vehicles, making it an ideal choice for surfaces that see regular use.

Examples include Old English chippings and red gravel.

18. Marble Chips

1marble chips. Jpg

Also known as marble gravels, marble chips are small pieces marble commonly used in landscaping and construction. They are made of metamorphic rock and have a natural sparkle which adds to their beautiful appearance as it reflects light. The bright colour and smooth texture make them ideal for luxurious, decorative applications.

Alpine blue gravel and onyx gravel.

19. Cotswold Gravel

1cotswold stone. Jpg

Cotswold gravel is a commonly used material for driveways and paths and is known for its warm, honey-coloured tones. This type of gravel has an angular shape, which helps it to interlock when compacted, creating a stable surface for walking and driving. Cotswold gravel is also frequently used in garden designs as it provides a traditional and rustic appearance.

Examples include Cotswold gravel and Derbyshire gold gravel.

20. Basalt Gravel

2black basalt

Basalt is a volcanic rock that is formed by the quick cooling of basaltic lava that is exposed at or near the surface. This rock is dark-coloured, fine-grained, and known for its durability, sleek appearance and resistance, which makes it suitable for a variety of construction and decorative landscaping purposes. It is can also be used for flooring, paving and as an aggregate in concrete. It most commonly available as Black basalt chippings.

21. White Gravel

2white marble gravel. Jpg

White gravel is a popular type of decorative aggregate, highly sought after due to it's bright white colour. Usually made from limestone or marble, it's reflective qualities can be used very effectively in landscaping to 'brighten up' areas or create striking visual contrasts.

Examples include polar white chippings and white limestone gravel.

22. Drainage Gravel

Drainage gravel is generally aggregates used to improve the drainage in outdoor spaces like gardens and driveways. The primary function of this gravel is to prevent soil erosion and water accumulation by allowing water to flow through it smoothly. It's commonly used in constructing French drains or soakaways.

20mm gravel or limestone chippings.

23. Lava Gravel

2lava gravel in a fish tank

Lava gravel is a type of volcanic rock that is sometimes used for landscaping, but more often for aquariums and hydroponics. It has distinctive look and excellent drainage. It typically comes in striking colours, such as red or black, which can add a dramatic touch to any application. Examples include natural red volcanic lava rock gravel.

The Pebble Picker

The Pebble Picker is a one of a kind search filter that enables you to select decorative aggregates according to their colour or type of material, among other parameters. It's a groundbreaking tool for the customisation of landscape design. It offer the entire range of colours and aggregate types accessible in the UK, simplifying the process of locating the perfect shades or materials for your needs. Whether it's a DIY garden design or an architectural project, our search filter ensures swift and easy access to the most comprehensive selection around. You can start playing by heading to the sidebar.

Summary

And that is the entire list of gravels available within the UK. If you believe that we have overlooked something that should be in the list, we would be more than happy to hear about it. Please drop us a line in the contact us page would be much appreciated. By understanding the different types of gravel and their beneficial qualities, you can make informed decisions when planning to renovate your outdoor space. And don't forget to try our aggregate matching technology in the sidebar - you will be amazed at the possibilities it can open up.

FAQs

How is pea gravel different from other types of gravel?

Pea gravel is distinct due to its small, round, pea-sized stones, offering a smooth texture. It's often used for paths and patios, contrasting with angular, larger stones used in construction.

What are the common uses of crushed stone gravel?

Crushed stone gravel is primarily used for driveway bases and construction projects, thanks to its angular shape and ability to compact, providing a stable surface.

What are the benefits of using limestone gravel?

Limestone gravel is valued for its durability, neutral colour palette, and ability to regulate soil pH, making it ideal for driveways, pathways, and garden beds.

Can I use granite gravel for a driveway?

Yes, granite gravel is an excellent choice for driveways. Its strength and variety of colours make it durable and aesthetically pleasing for high-traffic areas.

How does river rock gravel differ from other types of gravel?

River rock gravel, known for its smooth, rounded edges from water erosion, is larger and more decorative than other types, often used for garden beds and water features.

Is there a specific type of gravel suitable for garden pathways?

Pea gravel and decomposed granite are ideal for garden pathways, offering a stable yet soft walking surface and a variety of colour options.

Are there eco-friendly alternatives to traditional gravel options?

Eco-friendly alternatives include recycled glass gravel and crushed concrete. These sustainable options provide similar functionalities as traditional gravel.

How do I choose the right size of gravel for my project?

The right size depends on the project's purpose: fine gravel for pathways, medium-sized for general landscaping, and larger stones for drainage and decorative features.

We have every type of gravel available to choose from in the UK. Check them out!

About the author 

Ben Parrot is a landscape gardener and amateur geologist. He is the founder of Outdoor Aggregates, with the mission to create the first encyclopaedia for decorative aggregates. From natural stone through to decorative bark, these aggregates are critical to garden and landscape design, universally.

The problem: There isn't any place where all the different types of decorative landscaping materials and construction aggregates can be found, nor are the specifications of each type readily available. So, enriched by his extensive experience, and inspired by the timeless elegance and raw beauty of stone and rock, etched by nature's artistry over millennia, Outdoor Aggregates was born.